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.amr

AMR Audio

Audio

AMR is speech-oriented coding used in mobile recordings. Distinguish narrowband AMR-NB from AMR-WB. Exporting a voice-quality recording to WAV does not restore absent detail; inspect intelligibility, full duration and silent sections.

What it is used for
Mobile voice and speech recordings
What the file contains
Binary data
All sections, questions and sources

Content reviewed： · Editor：Kai

Opening steps

Choose your environment or purpose to see its steps.

Windows / Mac / Linux: inspect playback

Playback also depends on the encoded codec.

  1. Choose a copy through Open File in a compatible player such as VLC.
  2. Inspect the variant, such as AMR-NB or AMR-WB.
  3. Listen at the beginning, middle and end; check duration and whether audio is missing from one side.
Mobile / sharing: create a compatible copy

Check the receiving device’s accepted format.

  1. Play in the original recorder/messaging app and obtain a copy through sharing/export.
  2. If needed, create a separately named sharing copy using a compatible local converter.
  3. Test volume, duration, channels and title display in the actual destination.
Editing / storage: import into an audio application

Editing compressed audio does not restore missing original information.

  1. Decode through an AMR-capable tool and create a WAV editing copy if needed.
  2. Inspect silence and clipping in the editing copy and make only the required adjustments.
  3. Compare the output with the original and preserve the imported source.

Menu labels and support vary by app, OS and version. Preserve the original before making changes.

Troubleshooting by symptom

  • Music app fails: distinguish raw AMR from AMR inside 3GP.
  • Muffled speech: inspect source bandwidth/recording conditions; high-rate export adds no detail.
  • Ends early: compare duration/size against the original device recording.
  • Thin sound: inspect the speech recording bandwidth; WAV conversion cannot restore missing high frequencies.
  • Only AMR-WB fails: check narrowband and wideband support separately.
  • Recording ends early: compare original duration and exported size and request another export.

AMR → WAV / MP3

  1. Read with a tool supporting the correct NB/WB variant.
  2. Export separately and review the complete conversation, including beginning/end.
  3. Compare duration and representative passages after export, and check channels and tags.

AMR is lossy; MP3 adds compression and WAV does not restore missing detail.

Speech-oriented compression

AMR-NB and AMR-WB cover different speech bandwidths. Separate application compatibility from intelligibility.

Noise reduction can alter speech. Test on a copy and compare with the source.

Source for these steps：IETF · RFC 4867 — AMR and AMR-WB / VideoLAN · VLC Features

Sharing and storing a recording

Preserve date, duration and context alongside the audio; a converted filename may not retain message information.

Play the converted MP3/WAV to the end and inspect unexpected silence or truncation.

Source for these steps：IETF · RFC 4867 — AMR and AMR-WB / VideoLAN · VLC Features

Related-format differences

Related-format differences
FormatMain roleSelection notes
AMRCompressed speech recordingCheck NB / WB support
WAVEditable audio copyDoes not restore bandwidth
MP3Sharing with other devicesCheck speech after recompression

Handling and security

Speech recordings can contain personal information; confirm permission before sharing/storing.

Questions and answers

Are AMR-NB and WB identical?

No; their coding/bandwidth differs.

Can I restore high-fidelity music?

Lost source information cannot be restored.

May I rename it to 3GP?

Renaming does not create a container.

Can AMR become high-quality music?

Conversion cannot add original bandwidth or detail; use it for compatibility.

May I upload a conversation to a converter?

Assess the confidentiality of voices and content; prefer local conversion for private recordings.

Format facts: name, steward and MIME type
Formal name
Adaptive Multi-Rate audio file
Steward / specification
3GPP / IETF
MIME type
audio/amr / audio/amr-wb according to encoding

Primary and official sources

  • StandardRFC 4867 — AMR and AMR-WB

    Defines AMR/AMR-WB audio storage formats.

    IETF · Link checked：
  • Project documentationFormats Documentation

    Reference for handling TS, MP4, DVD and MXF containers.

    FFmpeg · Link checked：
  • Software documentationVLC Features

    VLC container, audio and video support.

    VideoLAN · Link checked：